Drop hammer



M. W. COLE Sgpt. 27, 1927.

DROP HAMMER 3 Sheefs-Sheet 1 Filed June 1 1925 (j MP? 2 'wcnlur Cale,

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M. w. COLE DROP HAMMER Filed June 19. 1925 s Sheets-Sheet s mnfor flf. W 00%;

Patented Sept. 27, 1927.

v UNITED STATES MARSHALL W. COLE, F RICHMOND, VIRGINIA n? HAMMER.

Application filed June 19, 1925. Serial No. 38,293.

This invention relates to improvements in drop hammers and particularly to an electrically operated drop hammer.

An object of the invention resides in pro- 5 ducing an electrically operated drop hammer, in which the re-action of a pair of energizedcoils is used to produce the lifting power for raising the hammer, wherein the arrangement of the coils is such that the reactive power becomes substantially neutralized, at the top of the stroke of the hammer so that it will be unnecessary to provide a stop to limit the upward movement of the hammer through the re-action between the energized coils.

A further object of the invention resides in providing an electrically operated drop hammer, including a base carrying guide 2 members for the hammer, at the upper end 0 of which is mounted a stationary coil for energizing the pole pieces carried at the upper end of the guide, which projects downwardly adjacent the opposite side and 5 through the hollow central portion of the hammer for generating a magnetic field, which will co-act with the field of the energized coil carried in the hammer, for producing an axial raising movement of the hammer guided in the guide ways of the sides, so that the hammer will be lifted through the re-action of these fields to the desired height for the following hammering operations The invention includes other objects and 0 improvements in the details of construction,

and arrangement of the parts, for embodying the invention in a practical construction, which may be made at a low initial cost, and which will have a substantially long life, as compared with types of drop hammers now in use, a preferred form of the invention being described and illustrated, it being understood, however, that variations may be made in the particular arrangement and construction of the parts for carrying out the object of the invention, without departing from the spirit and scope thereof as set forth herein. In the drawings, forming a part of this application Figure-1 illustrates a side elevational view of the improved drop hammer.

Figure 2 illustrates a. side elevational view of the drop hammer, taken at right angles to the view of Figure 1.

Figure 3 is a vertical sectional view, taken on the line 33 of Figure 2, showing parts in elevation.

Figure 4 is a horizontal sectional view, taken on the line 4-4; of Figure 1.

. Figure 5 is an enlarged detail view of the upper end portion, showing the inside face of one of the guide members.

Flgure 6 is an edge elevational view of the upper end portion of the guide member shown in Figure 5.

Figure 7 is a detail plan view of the upper end of the hammer.

Figure 8 is a detail bottom planview of the hammer.

1, indicates a base forming a support for the entire drop hammer construction, and a mountingfor the anvil 2 or stationary die with which the movable die co-operates in the hammering operation. At the opposite end of the base 1 are mounted a pair of guide members 3 extending upwardly from the base in parallel spaced relation.

The opposing faces of the guide members 3 are provided with vertically extending slots in which are mounted the guide rails 4, projecting inwardly from the guide members and forming the means for guiding the hammer or ram '5 in its movement by projecting into the slotted portion at opposite sides of the hammer formed by the projections 6 thereon. The central portion of the hammer is provided with a bore 7 and the lower end is provided with a dovetailed recess 8. which removably receives the movable die 9, for cooperation with the stationary die 2 in operation on the work to be hammered during operation of the device. The upper end of the hammer is provided with an enlarged annular recess 10, which receives the spool'll. on which is mounted the coil winding 12, to provide the armature for reaction in a stationary magnetic field for providing the lifting power for the hammer. The upperend of the hammer receives the plate 13 which .is secured thereto in any suitable manner for rigidly mounting the spool 11 within the recess 10. A bridge bar 14 is mounted across the upper ends of the guides 3 and is provided in the central ,portion with an upwardly extending cylindrical projection 15, which is flanged on the upper end, as at 16, to'provide a spool for receiving the stationary coil windings 17, adapted when energized to create the field for the armature coil 12, carried by the hammer.

A stationary inverted U-shaped pole structure is indicated by the numeral 18, which comprises a projection forming a central pole piece 19 inserted throughthe cylindrical projection on the bridge bar as illustrated in Figure 3, which extends into the bore 7 of the hammer. -This pole structure is also provided with a pair of extensions or arms 20 arranged in spaced parallel relation with respect to the central pole piece 19 and at opposite sides thereof to provide pole pieces for cooperation with the pole piece 19. The lower ends of the pole pieces 20 are extended inwardly, as indicated at 21 and provided with spaced plates 22, on the inner end faces thereof. This .pole construction 18 forms the magnetic circuit and field for the winding 17 so as to provide a stationary field at opposite sides of the armature coil 12 of the hammer, for re-action with the field of the coil, to produce the lift- I ing power for raising the hammer.

Bars 23 of non-magnetic material are connected to the ends of the pole pieces 20 and the edges of the guides 3, for mounting these pole pieces in rigid relation and to prevent undue vibration thereof in the operation of the hammer.

j The hammer is retained in raisedposition by a. latch lever 24, mounted in the recess 25, in one of the guide members 3, as illustrated in Figure 2, and which is movable in the I recess through the movement of the cam 26,

which engages in the recess in the end of the lever, so as to impart a sliding movementto the lever 24, in and out of the recess, toward or from the hammer. The cam 26 is carried on a suitable operating shaft 27,

having a hearing at one end in the guide member 3 and at theopposite end in the bracket, member 28, secured to the guide member 3, while the operating lever 29 has a suitable link connection 30, withthe foot lever 31, mounted on the base 1, so that the latch lever 24 may be suitably operated or the operation controlled by the operation of the foot lever. Suitable coil springs or other resilient means, indicated at 32 may be connected with the lever and the base, or otherwise suitably mounted,-for normally retaining the foot lever 31 in raised position and projecting the latch leverv into the path of movement of the hammer 5, so that each time said hammer is raised, the latch lever 24 will retain the same in the raised position'.

For the purpose of supplying current to the armature coil 12 ofthe hammer, suitable circuit connections are provided with opposite ends of the coil and the brush contact the circuit controlled thereby.

33 mounted on one side of the hammer and slidably engaging contact strips 34 mounted in the insulating strips 35, which are suitably secured in spaced relation at opposite sides of the guide bar 4, on the inner face of the guide member 3. This construction is particularly illustrated in its details in Figures 4 and 5. In the sliding movement of the hammer up .and down on the guide rail 4, it will be seen that the brushes 33 contact with the strips 34 in the respective insulating strips 35, and through the circuitconnects to the strips 34 will supply electrical energy to the coil 12 for energizing the same, in a manner to be'presently described. A switch mechanism for controlling the energization of the coil windings12 and 17 is mounted on one of the guide members 3 as illustrated in Figures 2 and 6 and includes a stationary contact member 36, suitably insulated from the guide members 3 and having the forked end 37 in which engages the switch arm 38, rockably mounted on the blocks 39. This block 39 is slidably mounted in the slot 40 in the guide 3, which is of dovetailed or T formation, so that a cooperatin section within theslot can be suitably tight.- ened together with the block 39, through the medium of the bolt 41, .for setting the'lever atthe desired point,'in order to time the closing of the circuit through the engagevment of the lever with the stationary contact 37. One end of the lever indicated at'42 extends into the path of movement of the hammer 5 so that when the hammer reaches the upper end of its stroke it will engage the end 42 of said switch lever and operate the same to disengage it from the forked end 37 of the stationary contact 36. The opposite end of the lever pivotally mounts a bar member 43 to which is connected one end of the coiled spring 44 having the opposite end connected to the bridge piece 14 for normally raising the bar 43 and operating the switch lever 38 so that it will engage in the forked end 37 of the stationary contact and close The lower end of the bar 43 is provided with an ax ially extending cylindrical guide 45 which jslidably receives the operating rod 46 pivotally connected at its lower end to the treadle 31 while the upper end is provided with a head 47 for engagement with the upper end of the guide 45. When the trcadle 31 is depressed the head 47 will engage the guide and operate to pull the bar 43 down to disengage the switch lever.38 from the stationary contact 36 while it at the same time operates the latch member 24 to release the hammer and permit the same to drop for the hammering operation.

In the operation of the drop hammer, of theabove described construction, the operator can control the operation of the hammer by the foot pedal 31. When it is desired to Y reduce a hammering operation, on work drop hammers an mserted on top of the anvil 2, the foot lever 31 is depressed, which will withdraw the latch lever 24 from engagement with the lower end of the hammer 5, and permit the hammer to drop. ,Upon releasing the treadle it will be seen that the switch 38 Will be moved by the spring 44. to close the circuit to raise the hammer. Upon the energization of the coils 12 and 17, a field will be set, up by the coil 17 between the pole pieces 20 and 19, in which the reaction of the coil 12 will operate to produce motion in an upward direction and lift the hammer to the upward limit of its movement sufiicientl'y to rise above the latch lever 24. At this point, due to the relation of the magnetic field created by the coil 17 and the coil 12, the armature coil 12 will be moved to substantially the neutral point of the field so that further upward movement will not take place, and the hammer will be maintained in a raised position. Due to this armature coil 12 moving to substantially a neutral point in the field of the coil 17, no impact will be occasioned on the hammer structure, in the upward movement thereof, and after the hammer reaches the upward limit of movement, it will engage the end of the switch lever 38 and move the same sufliciently to disengage the lever from the stationary contact 36, and

thereby break the circuit through the coil.

The lost motion between the rod 46 and bar member 43 permits this operation of the switch lever. If the operator of the hammer permits the foot lever to maintain its normal position, the latch lever 24 will engage the under side of the hammer and retain the'said hammer in its raised position. The same operation will again take place upon the depression of the foot lever 31 by the operator.

It will be noted that the constructio of the hammer is substantially simple, in rder that it may be manufactured at a relatively small cost, com ared with other types of that it is one which will withstand the heavy strain to which it is placed, resulting from the vibration caused through the hammering action, in the drop of the hammer. The special spool construc tion mounting the armature coil 12 on the hammer has been found to withstand the impact resulting from the operation of the hammer and to maintain its efficient operation.

It should therefore be fully appreciated that the relatively simple and efiicient construction has been produced for operating a drop hammer electrically, through the reaction of an energized armature coil, in a stationary magnetic field.

What is claimed is:

1. An electrically operated drop hammer,

comprising a base member rovided with an anvil, a hammer mounted or vertical reclp- 2. An electrically operate-d drop hammer comprising. a base member provided with an anvil, guide members extending vertically from the base member in spaced parallel relation, a hammer slidably mounted on said guide members for vertical reciprocating motion having a predetermined stroke, electrically energizable means for creating a magnetic field transversely of the path of movement of said hammer, and an armature coil carried by the hammer and energizable for re-action' in said field for producing power to raise the hammer to the top of the stroke, 'and means for controlling the energization of the electric means and the armature coil to prevent energization' of said means and coil during the downward movement of the hammer. J

3. An electrically operated drop hammer comprising a base member provided with an anvil, guide members extending vertically from the base member in spaced parallel re lation, a hammer slidably mounted on said guide members for vertical reciprocating motion, means'for creating a magnetic field transversely of the path ofmovement of said hammer, an armature coil carried by the hammer and energizable for vre-action in said field for producing power to raise the hammer to the top" of the stroke, means for controlling'the energization of theelectric means and the armature coil to prevent energization of said means and coil during the downward movement of the hammer, and means for retaining-the hammerat the up per end of the stroke.

4. In combination, a support, a pole structure mounted on the support having a plurality of spaced parallel projections forming pole pieces,a coil winding on said pole structure energizable to create a magnetic field across theends of said pole pieces, a member adapted for reciprocating movement between "member in registry with an opening formed in said bridge member, a pole structure formed of an inverted U-shaped member having a projection from the central portion between the ends and parallel therewith, said structure being mounted on said sleeve member, the projection extending through said sleeve member and the opening in the bridge, a hammer slidablc in the guides and around said projection, and means for operating the hammer. i

6. A drop hammer, comprising a base, spaced parallel guides mountedon the base, a pole structure mounted on said guides having a plurality of spaced parallel arms depending from and between said guides, a hammer slidable on said guides and between said arms, and cooperating means on the pole structure and hammer for operating 4 said hammer.

7. A drop hammer, comprising a base, 2

spaced parallel guides mounted on said base, a pole structure mounted on said guides having a plurality of spaced parallel arms dependin between said guides at opposite sides 0 the lane thereof, a hammer slidable on said gui es between said arms, cooperating means on the hammer and pole structure for lifting the hammer, manually releasable means for normally retaining the hammer in raised position, and means operated by the last-named means controlling the cooperating means.

In testimony. whereof I affix my signature.

MARSHALL W. COLE 

